Horrific video footage has emerged on social media, appearing to depict the killings of two Scandinavian university students, Louisa Vesterager Jespersen and Maren Ueland. One of whom is shown being decapitated, while they were hiking in Morocco’s Atlas Mountains.

Moroccan authorities say nine more people have been arrested in the gruesome slayings, which have been linked to suspected jihadists. The remains of Danish student Louisa Vesterager Jespersen, 24, and 28-year-old Norwegian Maren Ueland were flown out of Casablanca on Friday, bound for Copenhagen, a Moroccan police spokesman said.

Norwegian police, meanwhile, said they had no evidence to doubt the video’s authenticity, which showed Jespersen’s head being cut off.

Morocco’s Central Bureau of Judicial Investigations said the latest arrests were made Thursday and Friday across the country. With four other men arrested earlier, that brings the total number of suspects in the case to 13.

Louisa Vesterager Jespersen

Maren Ueland

Moroccan investigators say those arrested were carrying arms and “suspicious materials” used in making explosives.

The suspects were taken into custody for their “alleged links with the perpetrators of the terrorist act”, the bureau said.

The first four suspects had pledged allegiance to Islamic State (IS) group, Moroccan authorities said.

Louisa Vesterager Jespersen

The bodies of the two women were found Monday after they had pitched their tent at an isolated mountain site two hours’ walk from the tourist village of Imlil. One of them was beheaded, according to a source close to the investigation.

Imlil is a starting point for trekking and climbing tours of Mount Toubkal, which at 4,167 metres (13,700 feet) is the highest summit in North Africa.

Hours after the grisly discovery authorities announced the arrest of a first suspect and later said he belonged to an “extremist” group, while the three other suspects were arrested on Thursday.

Moroccan investigators are probing a link to Islamic extremism after a video emerged showing the suspects “pledging allegiance” to Islamic State, the Rabat prosecutor has said.

Authorities were working to determine the authenticity of a video posted on social media networks allegedly showing the murder of one of the women, according to the prosecutor.

Maren Ueland﻿

Louisa Vesterager Jespersen

“At this point, there is no tangible evidence that the video is not authentic,” Norway’s criminal investigations agency Kripos said on Friday.

The first four suspects were arrested in Marrakesh, an hour away from the scene of the murder.

Younes Ouaziad, 27, lived with his parents in the working-class Al-Azzouzia neighbourhood.

His family and neighbours said Friday they were “in shock”.

“He was a boy without any history, private. There was nothing to suggest he could do something like that,” said 35-year-old Abdelaati, a vegetable seller in the neighbourhood.

The murders have prompted condemnation from authorities in Denmark and Norway.

Danish Prime Minister Lars Lokke Rasmussen denounced what he called a “beastly crime”.

Norway’s Prime Minister Erna Solberg condemned what she called a “brutal and meaningless attack on innocents”.

Moroccan government spokesman Mustapha Khalfi described the killings as a “terrorist act” while Prime Minister Saad Eddine El Othmani said it was a “stab in the back of Morocco and Moroccans”.

Tourism is a cornerstone of Morocco’s economy, accounting for 10 per cent of national income.

Morocco has been spared jihadist attacks since 2011, when a bomb attack on a cafe in Marrakesh’s famed Jamaa El Fna Square killed 17 people, most of them European tourists.